What Is Glucose in a Blood Test?
Glucose is your body's primary energy source, regulated by insulin (lowers) and glucagon (raises).
Fasting Reference Ranges
- Normal: 70–99 mg/dL
- Prediabetes: 100–125 mg/dL
- Diabetes: 126 mg/dL+ (two separate tests)
- Hypoglycemia: below 70 mg/dL
- Random diabetes threshold: 200 mg/dL+ with symptoms
High Glucose Causes
- Diabetes (Type 1 or 2)
- Prediabetes
- Stress — illness, surgery
- Corticosteroids
- Pancreatic disease
- Pregnancy — gestational diabetes
Low Glucose Causes
- Diabetes medication — insulin or sulfonylureas
- Excessive alcohol
- Insulinoma — rare tumor
- Severe liver disease
- Adrenal insufficiency
Glucose vs HbA1c
- Fasting glucose = snapshot
- HbA1c = 3-month average
- HbA1c 5.7–6.4% = prediabetes
- HbA1c 6.5%+ = diabetes
- HbA1c is more reliable for diagnosis
Source: NLM MedlinePlus, American Association for Clinical Chemistry.
Ratings summarize government-reported measures — they don't capture your personal needs. Visit the facility, ask about staffing and services, and use CMS checklists. This profile is informational only and is not a recommendation.
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